284 The Evolution of Optics. 



the most satisfactory explanation of the origin of our color- 



It is asserted that color- vision is a later and more refined 

 sense than the vision of form, and it is well known that it is 

 presided over by a separate cerebral center. It is also sub- 

 ject to very frequent modifications ; for example, among the 

 sect of Quakers, which has existed only for a comparatively 

 short time, and who so religiously avoid all use of color in 

 dress, color-blindness is said to be proportionately greater 

 than among other communities. It is much more frequent 

 among men than among women, whose habits render color- 

 vision more important to them ; it is frequently transmitted 

 in the male line of a family through females possessing per- 

 fect color- vision. 



The color-sense is certainly capable of great education, 

 although it seems to be developed in the lowest races of 

 mankind. Goethe tells us that the mosaic workers in Italy 

 are in the habitual use of fifteen thousand varieties of hues, 

 each variety comprising fifty tints, a perfection of color- 

 sensation which is truly marvelous. 



"We can scarcely argue from the color-vision of man to 

 that of the lower animals. The color-sense is most highly 

 developed, no doubt, in many lower animals, but that their 

 perception of color is identical with ours is by no means 

 proved. In some cases we know definitely that the limits 

 of the visible spectrum are not the same. Lubbock has 

 shown this to be the case with ants by a series of very inter- 

 esting experiments. This fact alone should make us ex- 

 tremely cautious in assuming such identity. 



The eye, as we have seen, has developed in various classes 

 of animals in a somewhat different way, and it seems prob- 

 able that color-vision, which is a later development a re- 

 finement, as it were of light-perception, has been modified 

 by the structure of the eye and the habits of its possessor. 

 It seems much safer, therefore, to explain the human color- 

 sense in the manner we have just outlined than to trace it, 

 as is sometimes done, from animals far removed from man 

 in the line of descent. 



